JP4263641B2 - Rush adjuster - Google Patents

Description

  The present invention relates to a lash adjuster incorporated in a valve mechanism of an internal combustion engine.

  Conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-285807, a lash adjuster incorporated in an electromagnetically driven valve mechanism of an internal combustion engine is known. More specifically, the lash adjuster is incorporated between a valve shaft and an armature shaft of an electromagnetically driven valve mechanism, and includes a plunger body that contacts the valve shaft and a plunger that contacts the armature shaft. Yes. The plunger is inserted into the plunger body so that the outer peripheral surface thereof can slide with the inner peripheral surface of the plunger body.

JP 2002-285807 A

  In the lash adjuster described above, a clearance for leaking oil is provided between the plunger body and the plunger. Due to this clearance, when the lash adjuster is affected by a valve spring or the like, the plunger body and the plunger may slide in an inclined state. If the lash adjuster operates in such a state, problems such as malfunctions and uneven wear of the sliding parts occur. In order to cope with these problems, a method of suppressing the relative inclination between the plunger body and the plunger by increasing the length of the sliding portion can be considered. However, according to such a method, the overall length of the lash adjuster is increased, and further, the height of the valve operating system is increased.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a lash adjuster capable of realizing a suitable operation while suppressing an increase in the total length.

In order to achieve the above object, a first invention is a lash adjuster incorporated between a driven member that is operated by a driving source that generates a valve driving force and a valve interlocking member that operates in conjunction with the valve body. There,
A plunger body that has a cylindrical portion and a bottom portion that closes the cylindrical portion, and one of the driven member and the valve interlocking member abuts on the bottom portion;
A plunger abutting on the other of the driven member and the valve interlocking member and slidably disposed in the cylindrical portion of the plunger body;
The surface of the bottom portion is located within a sliding range of the plunger at a portion where the one member abuts.

  The second invention is characterized in that, in the first invention, a contact position between the plunger body and the one member is located within a sliding range of the plunger.

The third invention is a lash adjuster incorporated between a driven member that is operated by a drive source that generates a valve driving force and a valve interlocking member that operates in conjunction with the valve body,
A plunger body in contact with either one of the driven member and the valve interlocking member;
A flange portion that contacts the other of the driven member and the valve interlocking member, and a first portion that protrudes from the flange portion to the one member side so that the outer wall can slide with the inner wall of the plunger body. A plunger having a cylindrical portion and a second cylindrical portion provided so as to protrude from the flange portion to the other member side so that the outer wall can slide with the inner wall of the plunger body;
It is characterized by providing.

  According to the first invention, the length of the sliding portion between the plunger body and the plunger can be increased without increasing the total length of the lash adjuster. And the relative inclination of a plunger body and a plunger can be suppressed by lengthening the length. For this reason, according to the present invention, it is possible to provide a lash adjuster that suppresses malfunction and uneven wear of the sliding portion without increasing the overall height of the valve train.

  According to the second invention, the total length of the lash adjuster is increased by configuring the contact position between the plunger body and one member contacting the plunger body within the sliding range of the plunger. Without increasing the length of the sliding portion between the plunger body and the plunger.

  According to the third invention, by providing the second cylindrical portion on the other member side that contacts the flange portion of the plunger, the sliding portion between the plunger body and the plunger is increased without increasing the overall length of the lash adjuster. The length can be increased. And the relative inclination of a plunger body and a plunger can be suppressed by lengthening the length. For this reason, according to the present invention, it is possible to provide a lash adjuster that suppresses malfunction and uneven wear of the sliding portion without increasing the overall height of the valve train.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view showing a structure of a lash adjuster 10 according to Embodiment 1 of the present invention. A lash adjuster 10 shown in FIG. 1 is incorporated in an electromagnetically driven valve mechanism that includes an actuator that drives a valve body of an internal combustion engine. More specifically, the lash adjuster 10 is incorporated between a valve shaft 12 having a valve body fixed at the tip thereof and an armature shaft 14 having an armature made of a magnetic material fixed thereto. The lash adjuster 10 has a function of expanding and contracting as necessary to appropriately change the relative position of the valve shaft 12 and the armature shaft 14 so that a zero rush state is formed.

  The lash adjuster 10 includes a plunger body 16. The plunger body 16 has a cylindrical portion 16a whose upper end side is an open end. And the plunger 18 is arrange | positioned inside the cylindrical part 16a. The plunger 18 has a flange portion 18a and a shaft portion 18b provided at the center of the flange portion 18a. The plunger 18 is provided with a cylindrical portion 18c that protrudes downward from the flange portion 18a, that is, toward the valve shaft 12 side.

  A stopper ring 20 that restricts upward sliding of the plunger 18 is attached to the inner wall near the upper end of the plunger body 16. Therefore, the plunger 18 can slide in the plunger body 16 in the axial direction within a range allowed by the stopper ring 20. That is, the inner wall of the cylindrical portion 16a of the plunger body 16 and the outer wall of the cylindrical portion 18c of the plunger 18 slide against each other, and the sliding portion 22 between them secures a clearance that allows oil flow. Has been.

  In the lash adjuster 10, a pressure chamber 24 surrounded by the plunger body 16 and the plunger 18 is formed inside the cylindrical portion 18 c of the plunger 18 in order to realize the expansion and contraction function. A reservoir cap 26 and a diaphragm 27 are disposed at the upper end portion of the plunger body 16, and a reservoir chamber 28 surrounded by the plunger 18, the reservoir cap 26, and the diaphragm 27 is formed. The armature shaft 14 described above is in contact with the flange portion 18a via the reservoir cap 26 and the shaft portion 18b of the plunger 18. That is, the armature shaft 14 is in contact with the center portion of the flange portion 18a and pushes the flange portion 18a.

  The pressure chamber 24 and the reservoir chamber 28 are communicated with each other via a communication path 30 provided in the flange portion 18a and the shaft portion 18b of the plunger 18. A retainer 32 is disposed in the pressure chamber 24. The retainer 32 is biased toward the plunger 18 by a spring 34. Further, a check valve 36 is disposed in the retainer 32. The check valve 36 is urged toward the communication passage 30 of the plunger 18 by a spring 38. The pressure chamber 24 is separated from the reservoir chamber 28 by the check valve 36 closing the communication passage 30.

Next, the characteristic part of the lash adjuster 10 of this embodiment is demonstrated.
The “sliding range” shown in FIG. 1 indicates the sliding range of the plunger 18, and specifically refers to the range from the bottom surface 40 of the plunger body 16 facing the tip of the plunger 18 to the stopper ring 20. .

  As shown in FIG. 1, one end of the plunger body 16 is a closed end. Hereinafter, this end portion is referred to as a bottom portion 42. The bottom 42 is provided with a shaft insertion hole 46 into which the end 44 of the valve shaft 12 is inserted. Further, the bottom portion 42 is configured such that the center of the portion in contact with the end portion 44 of the valve shaft 12 is raised in the cylindrical portion 16 a of the plunger body 16.

  That is, the lash adjuster 10 of the present embodiment is more specifically positioned above the lower end of the sliding range so that the central surface 48 of the bottom portion 42 is positioned within the sliding range of the plunger 18. It is configured as follows. Accordingly, the end 44 of the valve shaft 12 is also configured to be located above the lower end of the sliding range of the plunger 18.

  In other words, the sliding range of the plunger 18 is configured to extend below the central surface 48 of the bottom portion 42. In other words, in the lash adjuster 10, when the plunger 18 is located at the lowest position (when the lash adjuster 10 is contracted to the minimum), the central surface 48 of the bottom 42 enters the cylindrical portion 18 c of the plunger 18. It is configured. In addition, as long as the surface 48 is located above the bottom face 40, the end 44 may be below the lower end of the sliding range.

  When an extension force, that is, a force that relatively separates the plunger body 16 and the plunger 18 is applied to the lash adjuster 10 configured as described above, the internal pressure of the pressure chamber 24 is lower than the internal pressure of the reservoir chamber 28. To do. As a result, when the check valve 36 is separated from the plunger 18, the communication passage 30 is opened, and the oil in the reservoir chamber 28 flows into the pressure chamber 24 through the communication passage 30.

  On the other hand, when a compression force, that is, a force for relatively bringing the plunger body 16 and the plunger 18 closer to each other is applied to the lash adjuster 10, the communication passage 30 is closed by the check valve 36, so that the internal pressure of the pressure chamber 24 is increased. Increases from the internal pressure of the reservoir chamber 28. As a result, the oil in the pressure chamber 24 flows into the reservoir chamber 28 from between the inner wall of the plunger body 16 and the outer wall of the plunger 18. Accordingly, the overall length of the lash adjuster 10 is reduced. The reduction in the overall length of the lash adjuster 10 means that the relative distance between the valve shaft 12 and the armature shaft 14 is shortened. Here, the amount by which the lash adjuster 10 is reduced within a predetermined time is referred to as “lift loss”.

  As described above, according to the lash adjuster 10 of the present embodiment, the plunger body 16 and the lash adjuster 10 are not changed without changing the relative positional relationship between the valve shaft 12 and the armature shaft 14, that is, without increasing the overall length of the lash adjuster 10. The length of the sliding portion 22 with the plunger 18 can be increased. And it can suppress that the plunger body 16 and the plunger 18 slide in the state which inclined relatively by making the length of the sliding part 22 long. For this reason, according to the lash adjuster 10 of this embodiment, the malfunction of the lash adjuster 10 and the partial wear of the sliding part 22 can be suppressed effectively, without increasing the height of the valve operating system.

  In an electromagnetically driven valve mechanism incorporating a lash adjuster, when the valve element is opened, the lash adjuster receives a compression force from the valve shaft and the armature shaft and contracts. When the valve body is closed after the lash adjuster is contracted, there may be a difference between the timing at which the valve body is seated and the timing at which the armature reaches the electromagnet. This timing shift becomes larger as the amount of reduction of the prior lash adjuster, that is, the lift loss increases. As the lift loss increases, the armature reaches the electromagnet more vigorously, and the operating noise increases.

  The above-described lift loss has a characteristic that depends on the clearance between the plunger body 16 and the plunger 18, and increases as the clearance increases. According to the lash adjuster 10 of the present embodiment, uneven wear of the sliding portion 22 can be suppressed, so that the change with time of the clearance can be suppressed, and as a result, the change with time of lift loss can be suppressed. For this reason, according to the lash adjuster 10 of the present embodiment, it is possible to suppress a change in the operating sound of the electromagnetically driven valve mechanism accompanying a change with time.

  By the way, in Embodiment 1 mentioned above, although the example in which the lash adjuster 10 was incorporated in the electromagnetic drive type valve operating mechanism was shown, the lash adjuster of the present invention is not limited to this, and the valve operating mechanism of various configurations is used. Can be applied. Specific examples are shown in FIGS. 2 to 5 below.

  FIG. 2 is a view showing a first modification of the valve mechanism in which the lash adjuster 10 shown in FIG. 1 is incorporated. The example shown in FIG. 2 is an example in which the lash adjuster 10 is turned upside down and applied to an electromagnetically driven valve mechanism with respect to the configuration of the first embodiment. As shown in FIG. 2, the valve shaft 50 is brought into contact with the plunger 18 via the reservoir cap 26, and the armature shaft 52 is inserted into the shaft insertion hole 46 of the plunger body 16. That is, in this example, the center surface 48 of the bottom portion 42 of the plunger body 16 that contacts the armature shaft 52 is configured to be located within the sliding range of the plunger 18.

  FIG. 3 is a view showing a second modification of the valve operating mechanism in which the lash adjuster 10 shown in FIG. 1 is incorporated. The example shown in FIG. 3 is an example in which the lash adjuster 10 is inverted and applied to a cam-driven valve mechanism. As shown in FIG. 3, the valve shaft 54 is brought into contact with the plunger 18 via the reservoir cap 26, and a lifter 56 made of a rotating body having a T-shaped cross section is inserted into the shaft insertion hole 46 of the plunger body 16. Has been inserted. That is, in this example, the central surface 48 of the bottom portion 42 of the plunger body 16 that contacts the lifter 56 is configured to be located within the sliding range of the plunger 18.

  FIG. 4 is a view showing a third modification of the valve operating mechanism in which the lash adjuster 10 shown in FIG. 1 is incorporated. The example shown in FIG. 4 is an example in which the lash adjuster 10 is applied to a cam-driven valve operating mechanism. As shown in FIG. 4, a lifter 58 made of a rotating body having a T-shaped cross section is brought into contact with the plunger 18 via a reservoir cap 26, and a valve shaft 60 is inserted into the shaft insertion hole 46 of the plunger body 16. Has been inserted. That is, in this example, the center surface 48 of the bottom portion 42 of the plunger body 16 that contacts the valve shaft 60 is configured to be located within the sliding range of the plunger 18.

  FIG. 5 is a view showing a fourth modification of the valve operating mechanism in which the lash adjuster 10 shown in FIG. 1 is incorporated. The example shown in FIG. 5 is an example in which the lash adjuster 10 is applied to a cam-driven valve operating mechanism. As shown in FIG. 5, a lifter 62 made of a rotating body having a U-shaped cross section is brought into contact with the plunger 18 via a reservoir cap 26, and a valve shaft 64 is inserted into the shaft insertion hole 46 of the plunger body 16. Has been inserted. That is, in this example, the central surface 48 of the bottom portion 42 of the plunger body 16 that contacts the valve shaft 64 is configured to be located within the sliding range of the plunger 18.

  Further, in the first embodiment described above, the central surface 48 of the bottom portion 42 of the plunger body 16 is configured to be located within the sliding range of the plunger 18, but the overall length of the lash adjuster 10 is increased. However, the configuration for increasing the length of the sliding portion 22 is not limited to this. In other words, the relative positional relationship between the valve shaft and the armature shaft does not change unless the distance between the bottom of the plunger body that contacts the valve shaft and the flange portion of the plunger that contacts the armature shaft changes. In the example of the first embodiment described above, the cylindrical portion 18c of the plunger 18 is extended downward from the flange portion 18a. However, the present invention is not limited to this, and the cylindrical portion of the plunger is extended upward from the flange portion of the plunger (that is, It is good also as providing the 2nd cylindrical part. Even with such a configuration, the length of the sliding portion can be increased without changing the relative positional relationship between the valve shaft and the armature shaft.

  In the first embodiment described above, an example of application to a closed oil type lash adjuster in which oil is sealed inside the lash adjuster 10 has been shown, but the present invention is not limited to the lash adjuster having such a structure. The present invention may be applied to an external supply type lash adjuster to which oil is supplied from the outside.

In the first embodiment and the modification thereof described above, the "driving source for generating the valve drive force" in the actuator or cam of the first invention of the electromagnetic drive valve operating mechanism, the armature shaft 14, 52 and the "driven member" lifter 5 6, 5 8, 62 in the first invention, the "valve interlocking member" in the valve shaft 12, 50, 5 4, 60, 6 4 the first aspect of the present invention, correspond is doing.
In the first embodiment described above, the cylindrical portion 18c of the plunger 18 corresponds to the “first cylindrical portion” in the third aspect of the invention.

It is sectional drawing which shows the structure of the lash adjuster of Embodiment 1 of this invention. It is a figure which shows the 1st modification of the valve operating mechanism in which the lash adjuster shown in FIG. 1 was integrated. It is a figure which shows the 2nd modification of the valve mechanism which incorporated the lash adjuster shown in FIG. It is a figure which shows the 3rd modification of the valve mechanism which incorporated the lash adjuster shown in FIG. It is a figure which shows the 4th modification of the valve operating mechanism in which the lash adjuster shown in FIG. 1 was integrated.

Explanation of symbols

10 Rush adjuster 12, 50, 54, 60, 64 Valve shaft 14, 52 Armature shaft 16 Plunger body 16a Plunger body cylindrical portion 18 Plunger 18a Plunger flange portion 18c Plunger cylindrical portion 22 Plunger body inner wall and plunger outer wall Sliding part 26 Reservoir cap 42 Plunger body bottom part 44 Shaft insertion hole 46 Plunger body side end part 48 of valve shaft Center surface 56, 58, 62 of bottom part of plunger body Lifter

Claims (3)

A lash adjuster incorporated between a driven member that is operated by a drive source that generates a valve driving force and a valve interlocking member that operates in conjunction with the valve body,
A plunger body that has a cylindrical portion and a bottom portion that closes the cylindrical portion, and one of the driven member and the valve interlocking member abuts on the bottom portion;
A plunger abutting on the other of the driven member and the valve interlocking member and slidably disposed in the cylindrical portion of the plunger body;
The lash adjuster characterized in that the surface of the bottom portion is located within a sliding range of the plunger at a portion where the one member abuts.   The lash adjuster according to claim 1, wherein a contact position between the plunger body and the one member is located within a sliding range of the plunger. 3. The lash adjuster according to claim 1, further comprising a pressure chamber formed by being surrounded by the plunger body and the plunger and in which an internal pressure increases when a compressive force is applied to the lash adjuster.

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